Well on my eyes this scenario justifies a tea bag, a Thorn scrub shoots you in the back, you then turn around and spray him down with the necrochasm finally securing the peashooter kill, that itself should be rewarded with tea bagging rights but then carrying on this new found courage, from going balls deep in a thorn scrubber's mouth, to kill two more of his thorn dwelling bum buddies. This feat I think is rewarded with the almighty rights to tea bag whilst shooting frantically in the air with every last round until the game is over. That constitutes in my mind as a moment of which tea bagging is exceptable.